1. Field of the Invention
The present invention primarily relates to single cylinder deadbolt locks installed on the doors of homes having the advantage of allowing a user inside the home to physically engage the latch with the backplate thereof when the deadbolt is latched, thereby preventing any would be intruder from entering the home by picking the lock. More particularly, the present invention pertains to a kit for modifying a single cylinder deadbolt lock found in most homes in order to provide the above mentioned advantage lacking in most single cylinder deadbolt locks. However, the same function may be applied at the manufacturing level.
2. Description of the Prior Art
Most deadbolt locks used in the average home are single cylinder locks having a key hole on the face of the lock located on the front side of the door and a latch on the opposite face side of the lock located on the back side of the door. Some of the deadbolt locks used in homes include a securing mechanism for preventing the latch from rotating from its locked position when the mechanism is engaged with the latch and some other object fixedly connected to the door. For example, U.S. Pat. No. 4,590,777, issued May 27, 1986 to Rafael Sierra, discloses a bolt lock which can be immobilized in the locked position.
A door latch is disclosed in U.S. Pat. No. 999,127, issued Jul. 25, 1911 to Joseph S. Slivenick, in which a screw having a knurled head is used to engage the bolt of the door latch.
A deadbolt locking device is disclosed in U.S. Pat. No. 5,052,202, issued Oct. 1, 1991 to Jerry A. Murphy. Murphy discloses a deadbolt locking device having a head portion including an aperture for engaging the latch of a deadbolt in the locked position as two leg portions engage the door handle to prevent the latch from rotating the head portion.
Means for preventing a deadbolt latch from rotating is disclosed in U.S. Pat. No. 5,003,803, issued Apr. 2, 1991 to Robert M. Richards, who discloses a plate having an aperture therethrough for allowing the latch of a deadbolt to fit therein. Once the latch is turned to the locked position, the plate is fit over the backplate and attached thereto with the latch being located within said aperture, thereby preventing the latch from rotating.
Another means for preventing a deadbolt latch from rotating is disclosed in U.S. Pat. No. 5,000,498, issued Aug. 3, 1990 to Lewis E. Upchurch. Upchurch discloses an adjustable clamp which can be fit over the latch and tightened down to securely clasp the latch. Once the latch is turned to its locked position, a sliding pin located at one end of the clamp can be slid into an aperture located on the door to prevent the latch from rotating.
A fastener for immobilizing a door handle once in the closed position is disclosed in U. K. Patent No. 1,564,607, issued Apr. 10, 1993 to Harry M. Williams.
Swiss Patent No. 185,383 issued Oct. 1, 1936 to Wilh. Schulte discloses a deadbolt lock arrangement having latch piece with an engaging member lockpost attached thereto for engaging the backplate once the latch is placed in its locked position.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.